1. Field of the Invention
The present invention relates to the field of displaying technology, and in particular to a color display device.
2. The Related Arts
An OLED (Organic Light-Emitting Diode) is a flat panel displaying technique of extremely prosperous future and it shows excellent displaying performance and also possesses various advantages, such as being self-luminous, simple structure, being ultra-thin, fast response, wide view angle, low power consumption, and being capable of achieving flexible displaying and is thus regarded as a “dream display”. In addition, the investment of manufacturing installation is far less than that of liquid crystal displays so that it has attracted the attention of major display manufacturers and becomes the mainstream of the third-generation display devices of the field of displaying technology.
Heretofore, several technical passageways have been proposed to achieve coloring of OLEDs, one being emission of light on the basis of three primary colors of blue, green, and red (RGB), of which Samsung Company is a representative manufacturer. This technique is only applicable to organic small molecule materials that are easy to sublimate but has advantages in respect of being a mature technique and easy to operate. However, due to the requirement of masks of high precision and alignment of high accuracy in making high resolution display screens, the productivity is relatively low and the cost is high. Further, due to the great difference in respect of lifespan, excitability, and degree of attenuation among the three primary colors, color shifting of a color display device may result.
Another technique is one that uses white light plus RGB filter (Color Filter, CF), of which a representative manufacturer is LG Corp. Since the mature technique of color filer of LCD is involved, there is no need for mask alignment, so that a vapor deposition process can be greatly simplified and the manufacture cost can be reduced, allowing for application thereof in manufacturing large-sized OLEDs of high definitions. However, since the color filter absorbs a great amount of optical energy, only 30% of the optical energy can transmit therethrough so that a white light material of high performance must be used, otherwise the efficiency of a display device would be relatively low and a general use being small molecule OLED display screens.
Inorganic quantum dot possesses advantages, such as photoluminescence, stable performance, long lifespan, wide absorption spectrum, and good color purity, and is widely used in fluorescent probes and medical diagnoses, making it an excellent photoluminescent material particularly suitable for serving as a material for a color filter (CF) or a color change material (CCM) layer of an OLED. However, applications in this field have not been known or proposed.
Thus, it is desired to develop a color display device of which the manufacture technique is simple, color purity is high, light effect is good, stability is high, and thickness is reduced.